Fluid pressure control mechanism



Nov. 20, 1951 R.' R. STEVENS FLUID PRESSURE CONTROL MECHANISM FiledApril 14, 1949 INVENTOR.

Roy R. Stevens 5%, ATToJavEY Patented Nov. 20, 1951 FLUID PRESSURECONTROL MECHANISM Roy R. Stevens, Forest Hills, Pa., assigner toWestinghouse Air Brake Company, a corporation of PennsylvaniaApplication April 14, 1949, Serial No. 87,441

1` Claim. 1

This invention relatesA to fluid pressure control apparatus of the typeused forselectively controlling multiple position clutches, gearchangers etc. where definite positioning is demanded.

One object of the invention is the provision of an improved controlapparatus of the above type.

Another object of the invention is the provision of an apparatus of theabove general type embodying an improved fluid pressure controlledpositioning motor and an improved manually operated fluid pressurecontrolling means therefor.

In certain reversing clutches, as well as gear changers, the clutchengagement or gear changer is maintained in a selected position afterbeing so placed by spring action through toggle mechanisms in overdead-center positions thereof, and also by quadrant and quadrant riders,etc. Power is therefore required only for moving the clutch or gearchanger control substantially into a selected one of its differentpositions and is not required for maintaining the clutch or gear changerin the selected position. In many cases it is not desirable to maintainpressure on the clutch or gear changer controls in that it causes unduewear to the shifting bearings.

Another object of my invention is therefore the provision of an improvedpower operated positioning apparatus embodying a multiple position iluidpressure actuated power motor for selectively positioning a device suchas a three position clutch or the like, and a valve means embodying aplurality of individual control valve units, corresponding in number tothe number of positions of the power motor, each manually operative tosupply lluid under pressure to said motor for effecting movement thereofto a corresponding selected position and operable automatically uponrelease of manual pressure to release fluid under pressure from saidmotor.

Other objects and advantages will be apparent from the following moredetailed description of the` invention.

In the accompanying drawing, the single figure is a diagrammaticview ofa control apparatus embodying the invention.

As shown in the drawing, the reference numeral I indicates a power motordevice for positioning a three position clutch control member 2, or thelike, and the numeral 3 indicates a manually operative control valvedevice for controlling said power motor device I.

The power motor device I, comprises two oppositely arranged cup-likecasing members 4 and 5, the casing member 4 having a bore 6 of onediameter and the casing member having a bore l of a larger diameter, thetwo bores being open at adjacent ends of said members and closed at theopposite ends. The casing members 4 and 5 are secured together with theboresG and 1 in fi. O

coaxial relationship and with a gasket 8;` sealing the jointtherebetween.

A piston 9 slidably mounted in the vbore B of casing 4 is provided withan annular groove ID in which is fitted a suitable sealing ring` Il.`having sliding and sealing engagement with the Wall of said bore. Thepiston 9 is solidly secured to one end of a piston rod I2 which extendsthrough a concentrically arranged opening I3 in the closed end wall ofthe bore 6. In the opposite or outer end of the piston rod l2 is ascrew-threaded bore in which is adjustably disposed the threaded end ofan eyebolt I4 which is adapted to be connected by a pin I5 to the deviceto be controlled such, as the clutch lever 2 which may have neutral,forward and reverse positions, as indicated by legends on the drawing.

Secured by a friction lit in the casing bore I3 is an annular member I6having an annular groove in its inner face in which is located a sealingring I1. This sealing ring I1 has a sliding and sealing engagement withthe peripheral surface of the piston rod I2 to prevent leakage of fluidpressure from the bore 6 to the atmosphere.

l The piston 9, the wall of bore 6, the closed end of the casing 4 andthe member I6 together with the seal Il define a chamber I8 which isopen at all times by a pipe I9 to the control valve device 3. Alsoincluded in the bore I3 of casing 4 is a felt ring 20, a metal washer 2|and a spring retaining ring 22 arranged in the order named with the feltring in engagement with member IS. The felt ring has sliding contactwith the piston rod I2 and is saturated with lubricant` in order tolubricate the bearing of said rod in member I6 and the Washer 2 I.

A piston 22 of suitable diameter is mounted Vin the bore 'l in casing 5.This piston is provided with an annular groove in which a sealing ring23, having sliding and sealing engagement with the wall of bore` l', islocated. The piston 22 is further provided with a cylindrical extensionmember 24 which extends into bore 6 of the casing member 4 and thereinterminates in an annular shoulder 25 which has a sliding` tin` bore B.This extension 24 and shoulder 25 form a guide member for the piston 22and also a stop member for piston 9 as will later be explained. Theclosed end of casing 5, the wall of bore 'l and the face of piston 22dene a iiuid pressure receiving chamber 26 which is open at all times bya pipe 21 to the control valve device 3.

The adjacent faces of pistons 9 and 22 and the walls of bores B and ldefine a third chamber 28 between said pistons which is open at alltimes to the control valve device 3 by a pipe 29. Ports 30 in theextension 24 permit a continual equalization of pressures on allportions of piston. 22 adjacent chamber 28. i

chamber'PI8, while pipes 21 and 29 and hence chambers 26 and 28 are opento the atmosphere,

the piston 9 will be moved by such fluidin thedirection of the left handinto` engagement with the piston extension 24, and if the piston 22 isnot already in engagement withashoulder 22a? in the casing the piston '9will move'piston 22 into such engagement whereupon movement of piston 9will be stopped by saidjextension Afor '1 positioning the clutch controllever 2 Ain its reverse position.

The power motor will denitely position the clutch control leverV '2 inthev forward'position defined by engagement of piston 9 with a shoulder9a in the casing upon supply of fluid pressure by p'pe 29 to chamber28while pipe I9 is open to the atmosphere, as will be apparent.VV

This fpower motor device Ywill denitely position the clutch controllever 2 in the neutral position, in which it is shown in the drawing,upon supply of fluid pressure via lpipes I9 and 2l to chambers I3 and26, respectively, while pipe 23 and hence chamber 26 are open to theatmosphere. The pressure of fluid thus provided in chamberY I8 andacting on piston 9 will urge said piston against the extension 24, whilepiston 22 being approximately twice thel area of piston 9 the pressureotfiuid in chamber 26 acting thereon Will provide a force so exceedingthe opposing force of piston 9 that even with the clutch control lever 2inpreverse position, the piston 22 will move both pistons againstpressure in chamber I3 until the piston 22 engages the open end of thecasing 4 in which position it is shown in the drawing.vv In thisposition of the piston 22, the extension 2li will hold the piston 9against pressure of fluid in chamber I8 in`a neutral position forcorrespondingly positioning the clutch control lever 2. The Ycontrolvalve device 3 comprises a casing 3l adapted to be mounted on a suitablepanel 32 or the like and containing a forward position valve unit 33, aneutral position valve unit 34 and a reverse position valve unit 35.

The three valve units 33, 34 and 35 are similar in construction eachcomprising a cylindrical body portion 36 formed with a plurality `ofsuccessively reducing diameters and inserted into a bore in the casingto a position in which a shoulder 3'I formed at the junction of asmaller diameter at one end and an intermediate diameter engages asuitable shoulder 3B formed at the junction of twobores of differentdiameter in the casing. The larger end of the body 3&3Y is provided witha bore 39 in which is located a release valve and a supply valve 4I. Asmaller bore 42 extends from the larger bore 39 through to the end ofthe smaller end of the'body por--` tion. In this bore 42 is located asupply valve stem 43 one end of which is connected to the supply valve.The supply valve stem extends beyond the valve body and is provided onits opposite end with a screw thread to receive a button 44 for manualoperation of the valvespas explained hereinafter.

A supply valve 4seat is formed on the body portion 36 around the endofbore 42 adjacent the bore 33 on which the supply valve is normally urgedto seat and a number of small ports 45 extend from the bore 42 adjacentthe supply valve seat to a port 46 in the casing 3I,'which port isnormally Vconnected by a pipe 4l to arluid pressure supply reservoirv(notshown?.q'lhe valve stem 43 is uted adjacent the supply valve toallow flow of supply .pressure past the supply valve `4 I when the valve4i`s"unseated and said stem is further "provided with a sealing ring 48'in a cylindrical portion of said stem in sealing contact with the wallof the bore 42 which prevents leakageofuid under pressure from the valveside of said ring to the atmosphere between the valve stem 43 andthebore 42.

The release yvalve 43 comprises a cup-shaped Vmember 49 slidably mountedin bore 39 and a rubber like composition valve seat 50 preferablyvulcanized to the inside of the cup for cooperation with a valve seat tobe hereinafter described. A spring 5I acting on the release valve 40normally supports it in an unseated position and urges thecontacting'supply valve 4I against its seat.

The larger open end of theV casing bore c ontaining the valve body 36 isnormally closed by a member 52 disposed in said bore with one side incontact with the adjacent and larger end of said body, while engagingthe opposite side is a removable spring type snap ring 53 a portion ofwhich ts into an annular groove in the casing open to said bore. Thering 53 retains the valve body 36 and the member 52 in the casing, butupon removal lof said ring and of button 134, these parts may beremo-ved from the casing. An extension 54 of member 52 projects into thebore 39 in the body 35 and on vits end there is provided a valve seatfor cooperation with the release valve 35. The spring 5I encircles theextension 54 and is supported by the Vmember 52. An exhaust port 55leads from the release valve seat to the lower sideof the member 52which in the casing of valve units 33 and 34 is exposed to atmosphere.In valve unit 35 this port 55 leads to a chamber 56 formed between thelower side of member 52 and a closing member 5l held in the casing by aremovable snap ring 57a. The member 51 is provided with a number of lugs5S which extend into contact with the member 52 or" valve unit 35 tosupport said valve unit in the casing 3|.

In each of the valve units a cavity 59 is formed in the casing 3l aboutthe lower end of the body 36. This cavity 59 is connected toa chamber 63formed above the exhaust valve 136 and containing the supply valve 4 I,by a number of ports SI in the body. The cavity 59 is also connected toa chamber at the opposite side of the release valve i6 by a number ofsmall ports r62.

VThe cavity 59 in valve unit 33 is connected by a port'63 to pipe 29leading to chamber 28 in the power motor I. In the valve unit 34 cavity59 is connected by a port 64 to the Vcavity 56 in valve unit 35 andY topipe 2`I leading to chamber 25 o1 the power motor I. In valve unit 35cavity'59 is connected by a Yport 65 to pipe I9 leading to chamber I8 ofthe power motor I.

Operation'of'apparatus Normally the buttons 44 of the three valve units33, 34 Vand 35 are relievedoi manual pressureV which in each valve unitpermits spring 5I to unseat the release valve 46 and to seat the` supplyvalve 4I. Chambers 28 and I8 in the motor I will therefore be normallyopen to atmosphere past the open release valves 40 in the valve units33, 34, respectively, while. chamber I8 in said motor will be open toatmosphere past the open release valve 46 in the valve unit 35 andthence through chamber-56,;portj64 and past the open release valifril:inthe, Valve unitn:- f. i

Now assuming that port 4I is connected to a suitable supply of fluidunder pressure, that the power motor I is positioned as shown in thedrawing and that it is desired to eiiect movement of the clutch controllever 2 to its forward position. The operator will apply suilicientpressurel to the button 44 of valve unit 33 to cause the supply valve 4Ito be unseated and to seat the release valve 40 therein against theopposing force of the respective spring 5l. Fluid under pressure fromthe supply pipe lll will then flow via port 46, and through the valveunit 33 via the respective ports 45, past the supply valve 4I, and portsy6I to cavity 59, and thence through port 63 and pipe 29 to chamber 28of the power motor. With chamber I8 open to atmosphere as aboveexplained, the pressure of iluid thus provided in chamber 28 will movepiston 9 toward chamber I8 until it engages the closed end of casing 4\thus moving the clutch control lever 2 to its forward position, Fluidunder pressure supplied to chamber 28 as just described will also movepiston 22 to its outer position in contact with stop 22a but withouterect or importance in the operation under consideration. After theclutch control lever 2 obtains its forward position the operator canremove his hand from the button 44 of the valve unit 33, whereupon insaid unit spring 5| will unseat the release valve 49 and seat the supplyvalve 4I. The supply of fluid under pressure to chamber 28 will therebybe cut off and the uid pressure in said chamber 2S will be released tothe atmosphere past the unseated release valve 49 in valve unit 33 andthrough port 55, for thereby, in the case of a clutch or the likerelieving the shifting bearings of actuating force.

To disengage the forward clutch by moving the lever 2 to neutralposition, the operator will apply suicient pressure to the button 44 ofvalve unit 34 to cause it to move downward for unseating the supplyvalve 4I and seating the release valve 48 therein. Fluid pressure isthereby admitted to port 64 and thence through pipe 2'I to chamber 26 ofthe power unit I and also from port 64 to chamber 5S of valve unit 35and thence through port 55 past the unseated exhaust valve 4U of unit 35to port 65 therein which is open to chamber I8 of the power unit I.Fluid under pressure thus supplied to chamber 26 will move piston 22toward chamber 28 until it engages the open end of casing 4, While thefluid under pressure provided in chamber I8 will move piston l9 towardchamber 28 until it engages the extension 24 of piston 22 in whichposition it will stop due to the larger area of piston 22. The piston 9as it thus moves will pull the clutch lever 2 to its neutral position. l

As soon as the clutch lever 2 obtains its neutral position the operatorwill remove pressure from button 44 of unit 34 to permit closing of thesupply valve 4I and opening of the release valve 48 therein to permitrelease of fluid under pressure from piston chambers I8 and 26 in motorI for relieving the clutch control lever 2 of actuating force.

To move the clutch control lever 2 to reverse positions, the operatorwill press the button 44 of valve unit 35 to unseat the supply valve 4Iand to s'eat the release valve 48 therein whereupon fluid under pressurewill be supplied to port 65 and via pipe I9 to chamber I8 of the powermotor I. The seatingpf the release valve 40 in unit 35 disconnects port65 from port E4 so that fluid under pressure will not be supplied to thelatter port which permits motor chamber 26 to remain open to atmospherethrough the unit 34. With the motor chambers 28 and 26 thus open toatmosphere the pressure of fluid provided in chamber I8 will move piston9 toward chamber 28 carrying with it piston 22 until the piston 22engages the closed end of casing 5 which limits the movement of piston'I to a position in which the clutch lever 2 is in its reverse position.After the clutch lever 2 obtains its reverse position manual pressure isremoved from the valve unit 35 to permit opening of the release valve 40and closing of the supply valve 4I therein. The fluid pressure inchamber I8 will then ow past the release valve of unit 35 to chamber 56,then to port 34 and to the atmosphere past the unseated release valve ofunit 34, for thereby relieving the clutch control lever 2 of actuatingforces.

In order to return the clutch control lever 2 from reverse position tc:neutral position the button 44 of the valve unit 34 need only bedepressed and then after the operation is completed said button may bereleased to relieve said lever of actuating force, as will be clear fromprevious description.

Summary From the above description it will now be seen that I haveprovided a control apparatus embodying a uid motor for positively,selectively positioning a multi-position device in accordance withselective manual operation of any one of a plurality of control valveunits, corresponding in number to the positions of said device, andwhich units are automatically operativeupon relief of manual force atthe termination of a selected operation to release actuating uid underpressure from the motor for relieving the device of operating force.

Having now described my invention, what I claim as new and desire tosecure by Letters Patent, is:

A control valve device for supplying iiuid under pressure to and forreleasing fluid under pressure from two control pipes, comprising acasing, two individual valve units in said casing each comprising asupply valve for supplying fluid under pressure to a chamber in theunit, a release valve seat, a release valve arranged to cooperate withsaid seat for controlling communication between said chamber and apassage opening to said seat, a push button manually operative to opensaid supply valve and to close said release valve, and a spring operableupon relief of manual pressure on said push button for closing saidsupply valve and for opening said release valve, said passage in one ofsaid valve units opening to atmosphere, the other valve unit furthercomprising means cooperative with said casing to form a chamber open tothe respective passage, means opening the last named chamber to the rstn-amed chamber in said one valve unit and to one of said pipes, andmeans opening the rst named chamber in said other valve unit to theother pipe.

ROY R. STEVENS.

REFERENCES CITED The following references are of record in the le ofthis patent:

UNITED STATES PATENTS Number Name Date 1,595,453 Doolittle Aug. 10, 19262,165,988 Stewart July l1, 1939 2,184,413 Chiesa Dec. 26, 1939

